Add a <canvas> element where you want to render an identicon. Use the data-jdenticon-value attribute to specify that an identicon should be rendered on the canvas. user127 below is just an example of a value.

<canvaswidth="80"height="80"data-jdenticon-value="user127"></canvas>

You may also opt for rendering vector icons. Use in this case <svg> elements instead of <canvas> elements.